The patch titled
usb-gadget-ether: Prevent oops caused by error interrupt race
has been removed from the -mm tree. Its filename was
usb-gadget-ether-prevent-oops-caused-by-error-interrupt.patch
This patch was dropped because an updated version will be merged
------------------------------------------------------
Subject: usb-gadget-ether: Prevent oops caused by error interrupt race
From: Benedikt Spranger <bene@xxxxxxxxxxxxx>
An USB error interrupt (e.g. disconnect) nukes the pending requests for an
ethernet gadget device asynchronously. This can race against
eth_start_xmit(), where we end up dereferencing the list head itself.
The nuke code is serialized against eth_start_xmit via dev->req_lock, but
we need to check the list for empty first instead of unconditionally
accessing dev->tx_reqs.next.
This is a long standing bug, which should be fixed in stable as well.
Signed-off-by: Benedikt Spranger <bene@xxxxxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: David Brownell <david-b@xxxxxxxxxxx>
Cc: Greg KH <greg@xxxxxxxxx>
Cc: <stable@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/usb/gadget/ether.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff -puN drivers/usb/gadget/ether.c~usb-gadget-ether-prevent-oops-caused-by-error-interrupt drivers/usb/gadget/ether.c
--- a/drivers/usb/gadget/ether.c~usb-gadget-ether-prevent-oops-caused-by-error-interrupt
+++ a/drivers/usb/gadget/ether.c
@@ -1957,8 +1957,20 @@ static int eth_start_xmit (struct sk_buf
}
spin_lock_irqsave(&dev->req_lock, flags);
+ /*
+ * dev->tx_reqs may be empty due to an error interrupt which
+ * nuked all requests.
+ */
+ if (list_empty(&dev->tx_reqs)) {
+ netif_stop_queue(net);
+ spin_unlock_irqrestore(&dev->req_lock, flags);
+ return 1;
+ }
+
req = container_of (dev->tx_reqs.next, struct usb_request, list);
list_del (&req->list);
+
+ /* last request in list: stop queue */
if (list_empty (&dev->tx_reqs))
netif_stop_queue (net);
spin_unlock_irqrestore(&dev->req_lock, flags);
_
Patches currently in -mm which might be from bene@xxxxxxxxxxxxx are
usb-gadget-ether-prevent-oops-caused-by-error-interrupt.patch
usb-gadget-ether-prevent-oops-caused-by-error-interrupt-race-v2-comments-update.patch
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